1. Field of the Invention
The present invention relates to a light emitting element using an inorganic material, and to a semiconductor device having a circuit including a light emitting element, and a manufacturing method thereof. For example, the present invention relates to an electronic device on which a light emitting display device having an inorganic light emitting element is mounted as a part.
Note that a semiconductor device in this specification refers to any type of device which can function by utilizing semiconductor characteristics. An electro-optical device, a semiconductor circuit and an electronic device are all included in the category of the semiconductor device.
2. Description of the Related Art
FIG. 10 shows a conventional structure of a light emitting element using an inorganic material. The light emitting element shown in FIG. 10 has a structure in which a lower electrode 2002, a first insulating film 2004, a light emitting layer 2006 including an inorganic semiconductor material, a second insulating film 2008, and an upper electrode 2010 are sequentially stacked over a substrate 2000. When a predetermined potential is supplied to each of the lower electrode 2002 and the upper electrode 2010, carriers (electrons) accelerated by a potential difference which is generated between those electrodes are trapped by impurity atoms in the light emitting layer 2006 or by an impurity level formed by the impurity atoms, and energy relaxation is caused. At that time, the energy is emitted as light.
In the case of using a metal material as a material of the lower electrode 2002 and the upper electrode 2010, light is emitted only in a direction parallel to a surface of the substrate 2000. Therefore, application to products is restricted.
A method for emitting light from an upper surface by making the thickness of the upper electrode 2010 using a metal material 5 to 20 nm is disclosed in Reference 1 (Reference 1: Japanese Published Patent Application No. 2004-221132).